Heat exchanger



June 13, 1961 T. L. WOOLARD HEAT EXCHANGER Filed April 18, 1958 United States Patent 2,988,336 HEAT EXCHANGER Thomas L. Woolard, Wellsville, N.Y., assignor to The Air Preheater Corporation, New York, N.Y., a corporation of New York Filed Apr. 18, 1958, Ser. No. 729,424 2 Claims. (Cl. 257-495) The present invention relates to improvements in plate type heat exchange apparatus utilized for the transmission of heat between confined fluids, and particularly it relates to an improved extended surface arrangement that greatly increases the transfer of heat between fluids on opposite sides of a passage wall in such heat exchange apparatus.

A well known form of heat exchange apparatus for the transfer of heat between two confined fluids comprises a plurality of spaced metallic plates forming passages through alternate ones of which a heating fluid flows in heat exchange relation with a fluid to be heated, the fluid to be heated traversing the intermediate passages. In many such heat exchangers a series of envelopes consisting of parallel plates with the space therebetween closed along one pair of opposite edges are provided. The envelopes are mounted in spaced parallel relation to form passages for another fluid and the inter-envelope spaces are similarly closed along one pair of opposite edges to restrict the fluid to the space therebetween.

To increase the efliciency of heat transfer between the two fluids that are spaced apart by the passage walls, the latter may be provided with extended surface in the form of pins or other surfaces that project into the fluid streams. In most cases the extended surface has been diflicult to fabricate, and generally the extended surface then provided has been inefficient or insufficient to satisfy the demands of the conditions involved.

Therefore, an object of the persent invention is to provide an improved extended surface arrangement for a plate type heat exchanger that is efiicient, adequate, and easily produced to satisfy various conditions.

The invention will be best understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawing in which:

The single figure is a perspective view of a heat exchange envelope constructed according to the invention.

In the drawing numeral represents the passage walls of a heat exchanger that are spaced apart by closure bars 12 to provide passageways therebetween for the flow of a heating fluid and a fluid to be heated.

To increase the transfer of heat between opposite sides of the passage walls, extended surface means is provided on one or both sides thereof. In accordance with this invention the extended surface is presented in the form of a plane metallic sheet 18 having rows of similar apertures 22 formed therein, the material from said apertures is bent out from the plane of sheet 18 to provide fins 24 attached to the sheet adjacent one side of each aperture. The opposite or free ends of the fins that lie remote from sheet 18 are adapted to lie in substantially the same plane so as to provide an even base for contact with an adjacent plate 10. In order that the fins 24 may be held in permanent contact with plate 10 the ends of the fins are bonded to the plate by any satisfactory process such as brazing, welding, or the use of a ceramic adhesive.

Such a plate 10 with integral finned sheet 18 thus becomes a basic extended surface unit for assembly into a plate type heat exchanger of the type defined.

In assembly a series of plates 10 with integral fin sheets '18 are spaced apart by closure bars 12 to provide an envelope enclosing a passageway for a first fluid. The space 28 between side walls of adjacent envelope assemblies is similarly enclosed on a pair of opposite sides by other closure bars to provide an enclosed passageway for the flow of a second fluid therethrough. A series of such envelope assemblies so joined together thereby provides a series of independent passageways through alternate ones of which one fluid may flow in heat exchange relation with the fluid in the intermediate passages.

Other extended surface means including finned sheets 18 made to predetermined standards may be placed in the inter envelope spaces by attaching to the adjacent walls thereof, and numerous other changes may also be made without departing from the spirit of the invention. It is therefore intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What I claim is:

l. A heat exchanger envelope adapted to transfer heat between two confined fluids comprising a pair of passage walls spaced apart by closure bars between one pair of opposite sides thereof; a pair of spaced metallic plates lying in parallel planes between said passage walls, said plates being formed with rows of apertures having the material therefrom bent normal to the plates to form rows of fins attached to one side to one of said plates and bonded at the opposite side thereof to the adjacent passage wall.

2. A heat exchange envelope adapted to effect the transfer of heat between spaced fluids comprising in combination, a pair of plane passage walls spaced apart by a pair of closure bars at opposite sides thereof to provide a passageway for one of said fluids; and a pair of metallic heat transfer plates lying in parallel planes between said passage walls, said metallic plates being formed with rows of apertures having the material therefrom bent similarly outward on a single side thereof toward .its adjacent passage wall to provide finned heat transfer plates having ojg lnlositely extending fins connected to the spaced passage w s.

References Cited in the file of this patent UNITED STATES PATENTS 1,597,885 Harris Aug. 31, 1926 2,002,923 Palmer a May 28, 1935 2,558,752 Holm July 3, 1951 2,632,633 Hammond et al Mar. 24, 1953 2,656,160 Lyerly et a1. Oct. 20, 1953 2,782,009 Rippinegille Feb. 19, 1957 FOREIGN PATENTS 662,375 Great Britain Dec. 5, 1951 

